Curtain walls are general used and applied in modern building constructions and are the outer covering of said constructions in which the outer walls are non-structural; but merely keep the weather out and the occupants in. Curtain walls are usually made of a lightweight material, reducing construction costs and weight. When glass is used as the curtain wall, a great advantage is that natural light can penetrate deeper within the building.
A curtain wall generally transfers horizontal wind loads that are incident upon it to the main building structure through connections at floors or columns of the building. Curtain walls are designed to resist air and water infiltration, sway induced by wind and seismic forces acting on the building and its own dead load weight forces. Curtain walls differ from store-front systems in that they are designed to span multiple floors, and take into consideration design requirements such as thermal expansion and contraction, building sway and movement, water diversion, and thermal efficiency for cost-effective heating, cooling, and lighting in the building.
However, architects and the public at large appreciate the aesthetics of glass and other light-transmitting materials used in the built environment. Light-transmitting materials, that serve both an aesthetic function as well as a structural function, are appreciated for their economy and visual effects. A common means prescribed by architects to achieve these goals in building structures is through the use of glass curtain wall systems.
A typical glass curtain wall structure is designed with extruded aluminum members. The aluminum frame is typically infilled with glass, which provides an architecturally pleasing building, as well as benefits such as daylighting. Usually, for commercial construction, ¼ inch glass is used only in spandrel areas, while 1 inch insulating glass is used for the rest of the building. In residential construction, thicknesses commonly used are ⅛ inch glass in spandrel areas and ⅝ inch glass as insulating glass. Larger thicknesses are typically employed for buildings or areas with higher thermal, relative humidity, or sound transmission requirements. However, outside-inside sound transmission correlation is usually relevant for all type of residential buildings.
With a curtain wall, any glass may be used which can be transparent, translucent, or opaque, or in varying degrees thereof. Transparent glass usually refers to vision glass in a curtain wall. Spandrel or vision glass may also contain translucent glass, which could be for security or aesthetic purposes. Opaque glass is used in areas to hide a column or spandrel beam or shear wall behind the curtain wall. Another method of hiding spandrel areas is through shadow box construction, i.e. providing a dark enclosed space behind the transparent or translucent glass. Shadow box construction creates a perception of depth behind the glass that is sometimes desired. Aesthetic design and performance levels of curtain walls can be extremely varied. Frame system widths, depths, anchoring methods, and accessories have grown diverse due to Industry and design innovation.
In general, a glass curtain wall structure or glass curtain wall construction is defined by an interior wall glass surface including one or more framing members and at least one floor spatially disposed from the interior wall surface. The gap between the floor and the interior wall surface of a curtain wall defines a safing slot, also referred to as perimeter slab edge (void), extending between the interior wall surface of the curtain wall construction and the outer edge of the floor. This safing slot is essential to slow the passage of fire and combustion gases between floors. Therefore, it is of great importance to improve firestopping at the safing slot in order to keep heat, smoke and flames from spreading from one floor to an adjacent floor. It is important to note that the firestop at the perimeter slab edge is considered a continuation of the fire-resistance rating of the floor slab. In general, the standard fire test method NFPA 285 provides a standardized fire test procedure for evaluating the suitability of exterior, non-load bearing wall assemblies and panels used as components of curtain wall assemblies, and that are constructed using combustible materials or that incorporate combustible components for installation on buildings where the exterior walls have to pass the NFPA 285 test.
In order to obtain certified materials, systems and assemblies used for structural fire-resistance and separation of adjacent spaces to safeguard against the spread of fire and smoke within a building and the spread of fire to or from the building, the International Building Code IBC 2012 provides minimum requirements to safeguard the public health, safety and general welfare of the occupants of new and existing buildings and structures. According to the International Building Code IBC 2012 Section 715.4, voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies shall be sealed with an approved system to prevent the interior spread of fire where fire-resistance-rated floor or floor/ceiling assemblies are required. Such systems shall be securely installed and tested in accordance with ASTM E 2307 to provide an F-rating for a time period at least equal to the fire-resistance-rating of the floor assembly.
However, there is a code exception that states that voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies, where the vision glass extends to the finished floor level, shall be permitted to be sealed with an approved material to prevent interior spread of fire. Such material shall be securely installed and capable of preventing the passage of flame and hot gasses sufficient to ignite cotton waste when subjected to ASTM E 119 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch of water column for the time period at least equal to the fire-resistance rating of the floor assembly.
5 Although some glass and frame technologies have been developed that are capable of passing applicable fire test and building code requirements, there is hardly any system that addresses the exception stated in the International Building Code IBC 2012 Section 715.4 and fulfills the code section ASTM E 2307 full-scale testing.
However, there is no system known that addresses above mentioned exception and at the same time complies with the requirements according to ASTM Designation: E1399-97 (Reapproved 2005), in particular having a movement classification of class IV, which addresses horizontal as well as vertical movements. The E 1399, Standard Test Method for Cyclic Movement and Measuring the Minimum and Maximum Joint Widths of Architectural Joint Systems, is used for simulation of movements of the ground, such as for example an earthquake, or even movements under high wind load or life load. In particular, there is no system known that is used in a curtain wall structure that provides a dynamic system complying with ASTM E 1399, such as for example a curtain wall structure defined by an interior wall surface, which includes an interior panel, such as a back pan, extending over the interior surface thereof and at least one floor spatially disposed from the inner wall surface, thereby sealing of the safing slot between the floor and the back pan of this curtain wall, which extends between the interior wall surface of the interior panel and the outer edge of the floor. Said safing slot is needed to compensate dimensional tolerances of the concreted floor and to allow movement between the floor and the façade element caused by load, such by life, seismic or wind load.
Due to the increasingly strict requirements regarding fire-resistance as well as horizontal and vertical movement, there is a need for a dynamic, thermally and acoustically insulating and sealing system for a curtain wall structure that is capable of meeting or exceeding existing fire test and building code requirements and standards including existing exceptions. In particular, there is a need for systems that prevent the spread of fire when vision glass of a curtain wall structure extends to the finished floor level below even when exposed to certain movements (complying with the requirements for a class IV movement). Further, there is a need for systems that address the architectural limitation of the width of a column or spandrel beam or shear wall behind the curtain wall. Additionally, maintaining safing insulation between the floors of a residential or commercial building and the exterior curtain wall responsive to various conditions including fire, wind and earthquake exposure should be guaranteed.
Further, there is a need for systems that can be easily installed within a safing slot, where, for example, access is only needed from one side, implementing a one-sided application. Further, there is a need for systems that are not limited to the width of a joint of a curtain wall structure thereby compensating at the same time dimensional tolerances of the concreted floor and allowing movement between the floor and the façade element caused by load, temperature or wind load. Moreover, there is a need for systems that improve fire-resistance as well as sound-resistance and can be easily integrated during installation of the curtain wall structure.
Still further there is a need for systems, that can be installed into a unitized panel, making it easier for the installers to the install the pre-assembled curtain wall panel on the job side.
In view of the above, it is an object of the present invention to provide a dynamic, thermally insulating and sealing system for effectively thermally insulating and sealing of a safing slot within a building construction, having a curtain wall construction defined by an interior wall surface including one or more framing members and at least one floor spatially disposed from the interior wall surface of the curtain wall construction, wherein the vision glass of a curtain wall structure extends to the finished floor level below.
Still further, it is an object of the present invention to provide a full-scale ASTM E 2307 as well as ASTM E 1399 tested system for floor assemblies where the vision glass extends to the finished floor level, to address the code exception, to avoid letters and engineering judgments, and to secure and provide defined/tested architectural detail for this application, in particular, by providing a tested system for fire- as well as movement-safe architectural compartmentation.
Still further, it is an object of the present invention to provide a tested system that utilizes no aluminum or faced curtain wall insulation, and the safing insulation can be pre-installed from one side, which maintains the safing insulation between the floors of a residential or commercial building and the glass curtain wall responsive to various conditions, including fire exposure, and maximizes safing insulation at a minimal cost.
Still further, it is an object of the present invention to provide a building construction comprising of such a dynamic, thermally insulating and sealing system for effectively thermally insulating and sealing of the safing slot between a glass curtain wall structure and the edge of a floor, in particular within the zero spandrel area, wherein the vision glass of a curtain wall structure extends to the finished floor level below.
Still further, it is an object of the present invention to provide a system that can be easily installed within a safing slot, where, for example, access is only needed from one side, implementing a one-sided application.
Still further, it is an object of the present invention to provide a system, that can be installed into a unitized panel, making it easier for the installers to build up the curtain wall on the job side.
Still further, it is an object of the present invention to provide at the same time an acoustic insulating and sealing system for effectively acoustically insulating and sealing of the safing slot between a curtain wall structure and the edge of a floor.
These and other objectives as they will become apparent from the ensuring description of the invention are solved by the present invention as described in the independent claims. The dependent claims pertain to preferred embodiments.